Air admission means and explosion relief safety door for combustion chambers



g- 1950 H. WEYENBERG EIAL 2,517,816-

AIR ADMISSION MEANS AND EXPLOSION RELIEF SAFETY DOOR FOR COMBUSTION CHAMBERS Original Filed June 19, 1944 INVENTORS. Henry lflgyener ll aliierjilli'mbew Patented Aug. 8, 1950 UNITED STATE AIR ADMISSION MEANS AND EXPLOSION RELIEF SAFETY DOOR FO-R COMBUS- TION CHAMBERS Henry Weyenberg and Walter R. Kimberley, Holland, Mich, assignors to Holland Furnace Company, Holland, Mich., a corporation of Delaware Original application June. 19, 1944, Serial No. 540,912. Divided and this application May 28, 1945, Serial No. 596,360

Claims. (o1. 11045) i This invention relates to heating and ventilating apparatus and is concerned especially with a combination unit embodying a combustion chamber having means supplying primary air for combustion thereto and means for supplying secondary air to the combustion chamber.

This application is a division of our copending application, Serial No. 540,912, filed June 19, 1944, now abandoned.

Among the objects of our invention is to provide a combustion chamber particularly adapted for use with oil as a fuel and designed to control the admission and regulation of secondary air to the combustion chamber adjacent the upper edge of the firebox.

A further object of the invention is to provide a heating plant which includes a combustion chamber and means operating automatically to relieve excessive gas pressure in the chamber so as to prevent dangerous explosions in the event of the temporary generation of gas which is not burned up in the normal manner nor carried off by the stack.

Another object of the invention is to provide a heating plant which includes a combustion chamber and an air feeding structure having an inclined inner flange and .a safety door, the inclined flange tending to divert excess pressure toward the safety door and away from the means for controlling the air inlet.

Other objects, advantages, and capabilities inherently possessed by our invention will later more fully appear.

In the drawings:

Fig. 1 is a. fragmentary vertical section through a central plane and showing certain parts in elevation for clearness.

Fig. 2 is a fragmentary enlarged vertical section taken on the same plane as Fig. 1 and showing the air feeding structure.

Fig. 3 is a fragmentary front elevation taken as indicated at line 3-3 of Fig. 1.

While the invention is susceptible of various modifications and alternative constructions, the embodiments shown in the drawings and herein described are by way of preferred illustration only, and it is not intended that the invention be limited thereto or thereby, but it is the intention to cover all modifications and alternative constructions falling within the scope of the invention as defined by the claims.

The apparatus shown in the drawings is mainly enclosed in a cabinet or casing having outer wall I designed to afford a clean-cut and pleasing appearance and adapted to be finished attractively in color, if desired. Ordinarily, the outer walls will be formed of sheet metal panels suitably connected at the corners and edges; the cabinet being divided at about the middle of its length fore-and-aft by a transverse vertical partition 4 and the heating unit is located in the forward compartment while the air circulating apparatus is disposed in the rear compartment '5 thus formed. As shown in Fig. l, a pressure oil burner having a mixing and fuel feeding mechanism mounted at 6 in front of the cabinet is provided with a discharge tube 6a from which the flaming fuel is blown into a firebox l which is an upwardly Open chamber composed of suitable refractory material, such as fire-clay or fire-brick. The firebox I is mounted upon the cast metal bottom 8 of the combustion chamber 9, this bottom wall having feet ID by which it is supported ata short distance above the floor to permit the circulation of air under it and to avoid undue heating and warping of the cast bottom 8 by reason of its proximity to the firebox I.

The combustion chamber sis in the form of a vertically extending sheet metal cylinder in which the firebox I is mounted in substantially coaxial relation and the cylindrical wall of the chamber 9 is spaced inwardly from the outer walls I of the enclosing cabinet to provide a space II for circulation of air blown thereinto from the blower I3 through the blower outlet I4. The air thus forced into the space II travels upwardly therein and absorbs heat which is radiated from the cylindrical wall of the combustion chamber 9.

Provided between the combustion chamber 'walls9 and the outer casing I is an inner lining I6 which consists of sheet metal plates spaced a short distance inwardly from the outer walls I of the cabinet at the front and sides thereof so as to provide vertically extending air spaces through which some of the air discharged from the blower outlet I4 will flow upwardly adjacent the outer wall I while the remainder of the air is passing upwardly between the lining I6 and the-cylindrical wall of the combustion chamber 9. The interposed lining I6 will prevent the rapid transfer of heat to the space between this lining and the outer walls I; this space being open at the bottom as shown at I! which insures a constant upward movement of the air in this space allowing it little time to absorb heat from the lining or to transfer heat to the outer walls I. In other words, the upwardly flowing air in the spac'e between the walls I and the lining It becomes an insulating blanket which effectively prevents the excessive radiation of heat into the basement or other room in which the heatin apparatus is installed. There is no occasion for such insulation at the partition 4, since this is an interior wall of the cabinet and is not directly exposed to the air in the room. To facilitate the air flow through the insulating space or jacket the lower edges of the lining l6 may be flared inwardly, as shown at l9.

The flame in the combustion chamber 9 will ordinarily rise to a considerable height above the refractory firebox 1, attaining a temperature of approximately 1600 F.

The fuel discharge tube 6a of the oil burner 6 is located and steadied in the front wall of the enclosing casing by means of a collar 50. A cast panel is set in the front wall I of the casing structure and has a circular opening at 52 to receive the tube 6a; and said opening is formed in an annular recess 53 to accommodate a packing ring 54 of asbestos or the like which is held in place by the collar 50, which is angular in cross section, and is provided with set screws 55 by which it is secured on the tube 5a in position to hold the asbestos ring in the recess 53.

The same cast panel 5| carries the overflre control which includes an opening 56 at which there is secured an inwardly extending annular conically tapered flange 51 held in place by a central bolt 58 connecting a spider at the inner end of the flange with a spider formed across the opening 55. The outer end of the bolt 58 carries a, valve disk 59 which is threaded thereon and may be adjusted toward and from the rim of the opening 56 to provide an annular air inlet port Ell through which secondary air is supplied to assist combustion in the chamber 9, it being understood that primary air will be supplied to.the firebox from the oil burner 6. The

valve 59, being screwed onto the outer end of the bolt, may be manually adjusted by means of its radial flanges 6| to vary the capacity of the air inlet as desired.

The purpose of the inwardly projecting and conically tapered tubular flange 51 is to absorb the force of slight explosions or puffs of gas pressure which may occur occasionally in the combustion of the oil vapor, said flange tending to bafile the normally open annular outlet 66 and thus break up the force of any momentary pressure while eventually relieving the pressure through said outlet.

In the event of a more violent explosive action within the combustion chamber a hinged safety door 62 carried by the panel 5| acts as a safety valve and swings open to immediately relieve the excessive pressure, and being carried by hinge arms 63 extending from its upper edge, this door will close automatically by gravity after the pressure is relieved and will hang normally at closed position in a plane slightly inclined to the vertical, as seen in Fig. 2. The safety door 52, being located above the level of the rim of the firebox is flttedwith a movable inspection slide 64 having a handle 65 by which it may be swung We claim:

1. In a furnace structure adapted for use with a pressure oil burner, walls enclosing a combustion chamber and having means for supplying primary air for combustion thereto and a secondary air inlet, a fire box having an open top and side walls formed with an opening for receiving one end of said primary air supplying means to introduce said primary air first into the fire box and then into the combustion chamber, said secondary air inlet having an inwardly extending conically tapered tubular flange of constantly decreasing cross section from its outer to its inner end opposite the top of the flre box, a valve disk adjustably mounted over the large end of said secondary air inlet, and an inclined outwardly opening gravity-closing safety door directly above the secondary air inlet, the inclined outer upper surface of said conically tapered flange deflecting the force of explosion puffs of gas pressure toward and directly against the inher face of said safety door.

2. In a furnace structure in combination, walls enclosing a fire box and a combustion chamber above the fire box, said walls having means for supplying primary air for combustion to the fire box and combustion chamber and a secondary air inlet, said secondary air inlet having an inwardly extending tapered-tubular member open at both ends and closed around its circumference and of constantly decreasing cross section from its outer end to its inner end, a valve disk adjustably 'mounted over the large end of said secondary air inlet, and an inclined outwardly opening gravity-closing safety door directly above the secondary air inlet, the inclined outer upper surface of said tapered tubular member deflecting the force of explosive puffs of gas pressure toward and against the inner face of said safety door to open the same and relieve the force of said puff 3. A furnace structure as claimed in claim 2, in which the space inside of the safety door and immediately above and around the tapered tubular member is free of obstructions and open whereby part of the force of explosive puffs will pass from the inclined outer upper surface of the tubular member directly to the safety door.

4. In a furnace structure, walls enclosing a flre box and a combustion chamber, means for supplying primary air to the combustion chamber, said walls being formed with a secondary air inlet having an inwardly extending tapered tubular flange openat both ends and of constantly decreasing cross section from its larger outer end to its smaller inner end, a valve member adjustably mounted at said outer end, and an inclined outwardly opening gravity-closing safety door directly above said tapered tubular flange, an outwardly and upwardly inclined bottom wall in the opening covered by the safety door, said inclined bottom wall and a longitudinal element in the top of said tapered tubular flange falling in substantially parallel planes, whereby a substantial part of explosive puffs in the combustion chamher will be directed away from the secondary air .inlet and guided to the safety door.

5. In a furnace structure, walls forming a combustion chamber, a flre box in the combustion chamber, oneof said walls having three openings one above the other laterally adjacent the fire box, oneof said openings having primary air supplying means passing therethrough, the next higher opening having secondary air inlet means,

6 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 518,054 Craney Apr. 10, 1894 524,248 Harkins Aug. 7, 1894 577,527 Hulbert Feb. 23, 1897 610,260 Culter Sept. 6, 1898 1,108,698 Castle Aug. 25, 1914 1,287,852 Bozard Dec. 17, 1918 1,702,929 Breese Feb. 19, 1929 1,810,697 Dibble June 16, 1931 2,026,387 Jackes Dec. 31, 1935 

